Burger is pasteurized. Ground meat is way more likely to carry pathogens than whole muscle, because the outside surface, where bugs live, becomes mingled with the inside and free to wander.
Your steak is finally medium, says the USDA, who are trying to keep you alive and bless them for that, but that is some tough meat according to everybody trying to eat it.
According to the government, well-done steak is pulled off the grill and served to you philistines, probably with ketchup.
Chicken and other poultry are instantly pasteurized. You can cook to this temp without ruining the meat, but much higher and Meathead warns “you’ll be eating cardboard.” Instead, try out his high/low heat zone method. “You don’t wanna go higher than 165º F, otherwise it’ll dry it out,” he explains. “But let’s say you’re going for 160º F -- if you start it on the indirect side and gently warm it, and bring it up to say, 150º/155º F, you’re still at a risky temperature, and your skin is still soft and rubbery.